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April  34tl|.  19Dr 


BUREAU  OF  GOVERNMENTAL  RESEARCH 

LIBRARY 
44  LIBRARY  BUILDING 


REPORT 


of  the 


Sub-Committee   on  Statistics 


To  the  Chairman  and  Committee  on  Reconstruction, 
Gentlemen : 

The  Sub-Committee  on  Statistics  submits  the  following 
report.  Owing  to  the  strenuous  duties  of  each  one  of  itg 
members  and  the  difficulty  of  getting  detailed  statistics 
of  accuracy  without  a  large  force  of  reliable  clerks,  the 
data  collected  are  not  as  extensive  as  is  desirable.  The  funds 
at  the  disposal  of  the  committee  have  been  small;  $150.00 
made  available  on  September  5th,  1906,  and  $75.00  made 
available  on  April  llth,  1907. 

The  shock  occurred  early  in  the  morning  of  April  18th, 
1906.  The  number  of  'breaks  in  the  water  mains  was  over 
300  and  more  than  23,000  service  pipes  were  broken  at  once 
or  by  the  subsequent  fire.  (Map  11  of  the  Report  of  the 
Chief  Engineer  of  the  Spring  Valley  Water  Works,  July 
23rd,  1906),  and  all  of  the  supply  mains  leading  into  the 
city  from  storage  reservoirs  and  the  distributing  mains 
from  service  reservoirs  were  ruptured.  (See  Report  of  the 
Sub-Committee  on  Water  Supply,  pages  4-5).  These  dam- 
ages, coulpled  with  the  fatal  injury  of  the  Chief  Engineer 
of  the  Fire  Department,  entirely  crippled  that  department. 
The  consequent  losses  by  fire  far  exceeded  the  damages  by 
earthquake. 


BUREAU  OF  GOVERNMENTAL  RESEARC 

i  IRRARY 


The  Sub-Committee  prepared  the  following  outline  of 
its  investigations,  which  was  approved  by  the  General  Com- 
mittee : 

OUTLINE   OF   STUDIES    FOR    COMMITTEE    ON    STATISTICS. 

(A)  Extent  and  Losses  by  Fire. 

(B)  Earthquake  effects  on. 

(1)  Small  frame  'buildings,  wooden  underpinning. 

masonary  foundation. 

(2)  Large  frame  -buildings,  wooden  underpinning. 

(3)  masonary  foundation. 

(4)  Brick  and  wood  buildings,  Class  "B." 

(4a)       "  "  "  "        "in  process  of 

construction. 

(5)  Brick  and  wood  buildings,  Class  "C." 

(5a)       "  "  "  "        "in  process  of 

construction. 

(6)  Steel  cage  buildings, 

(6a)       "  in  process  of  construction. 

(7)  High  chimney  stacks. 

(8)  Chimneys, 

Lime  mortar. 
Cement  mortar. 
Cement-lime  mortar. 

(9)  Retaining  walls, 

(9a)  Surcharged  retaining  walls. 

(10)  Miscellaneous  structures. 

GENERAL  REMARKS  AND  SUGGESTED  CORRECTIONS 
IN  CONSTRUCTION  AND  BUILDING  LAWS 

In  presenting  data  the  Sub-Committee  feels  justified  in 
adding  general  remarks  and  suggestions  based  upon  its 
Observations  under  each  sub-heading. 

The  suggestions  and  recommendations  are  submitted 
with  the  hope  that  they  will  be  fully  considered  by  owners, 
and  that  they  may  result  in  the  most  scrupulous  regard  of 
all  provisions  of  the  architect  ani  engineer  when  stability 
and  safety  are  concerned,  whether  as  regards  fire  or  earth- 
tfuake.  With  the  lessons  before  us  it  is  the  unanimous 


opinion  of  your  Sub-Committee  that  the  greater  portion  of 
the  loss  sustained  cou'ld  have  been  prevented  by  a  clear 
interpretation  and  regard  for  the  lessons  of  1868  and  the 
fires  which  have  devastated  tihis  and  other  cities. 

Even  in  the  destruction  of  water  mains  it  is  apparent 
that  with  mains  'Constructed  on  solid  ground  or  adequate 
foundations  over  'critical  ground  and  with  ample  service 
reservoirs  and  fire  cisterns,  and  with  well  equipped  fire-tug 
service  having  shore  connections  to  mains,  our  disastrous 
losses  of  hundreds  of  millions  of  dollars  would  have  been 
measured  by  tens  of  millions  and  probably  by  a  less  sum. 

AREA    BURNED    AND    LOSSES    BY    FIRE 

The  area  of  the  burned  district  is  estimated  by  the  City 
Engineer  at  four  and  seven-tenths  square  miles  (4.7  sq.  m.). 
This  area  'comprised  521  blocks,  of  which  13  were  saved  and 
508  burned.  A  careful  classification  and  count  of  the  build- 
ings in  these  'blocks  was  made  from  the  block  books  of  the 
Norwich  Union  Insurance  Co.,  under  the  direction  of  this 
Sub-Committee.  This  count  shows  that  the  following  num- 
bers of  buildings  were  burned : 

Wooden  framed  buildings 24,671 

Brick-^Classes  C  and  B 3,168 

Brick  and  wood  (unclassified) 259 

Fire  proof  Class  A 42 

Stone 15 

Corrugated  iron  (wooden  frame) 33 

Total*   28,188 

*An  independent  estimate  by  the  Fire  Underwriters  Bureau  gave 
several  thousand  less.  A  comparison  of  the  bases  of  the  two 
counts  showed  that  the  Sub-Committee  estimated  each  separate 
building  with  independent  entrance  as  a  building.  The  insurance 
rules,  however,  classify  several  such  structures  as  one.  When  this 
was  compared  the  above  was  adopted,  by  the  Fire  Underwriters 
Bureau. 

3 


ESTIMATE  OF  THE  LOSS  IN  BUILDINGS 

A  careful  compilation  from  the  books  of  the  Assessor's 
Office  shows  that  at  the  assessment  prior  to  the  fire  these 
buildings  were  assessed  at  $52,504,240.00.  As  the  assess- 
ment on  this  class  of  property  is  generally  50%  of  its  market 
value,  the  loss  in  this  class  of  property  may  be  safely  put 
at  $105,008,480.00.  In  addition,  39  buildings  owned  as 
church  property  and  non-assessable  were  burned;  also 
municipal  and  buildings  used  for  public  purposes,  such  as 
the  California  Academy  of  Sciences,  Libraries,  etc. 

No  estimate  can  be  made  by  the  Committee,  with  the 
means  at  its  disposal,  as  to  the  value  of  merchandise,  per- 
sonal property,  records,  libraries,  scientific  collections,  etc. 
These  properties  were  in  some  instances  inestimable. 

Every  public  and  nearly  all  private,  professional  and 
general  libraries  were  destroyed.  All  public  records  of 
property  which,  with  the  pu'blic  utilities,  stocks  of  mer- 
chants and  manufactures,  must  have  aggregated  an  equal 
sum. 

BLOCKS    AND    BUILDINGS    IN    THE    BURNED    DISTRICT 
WHICH    WERE   SAVED 

Within  the  burned  district  13  blocks  were  saved.  The 
buildings  in  these  blocks  are  as  follows: 

Wooden  283 

Brick — Classes  B  and  C 13 

Brick  and  wood  (unclassified) 4 

Iron  (wooden  framed) 3 

Total  buildings  saved 303 

The  notable  instances  of  these  blocks  were : 
(1)  Masonry  warehouses  and  wooden  buildings  on  Tele- 
graph Hill  and  at  its  east  base,  covering  about  11  blocks  of 
land  bounded  by  Kearny,  Lombard,  Montgomery,  Chestnut, 
The  Seawall,  Filbert,  Sansome,  Green,  Montgomery  and  Fil- 
bert to  Kearny.  These  were  saved  principally  by  water 

4 


pumped  by  tugs  from  the  bay  and  by  the  pumps  of  the 
cold  storage  plant. 

(2)  About  two  blacks  of  frame  and  plastered  buildings 
on  Russian  Hill  at  Jones  and  Green  streets,  saved  by  reason 
of  isolation  and  a  small  local  supply  left  in  the  service 
reservoir. 

(3)  The  U.  S.  Custom  House  and  the  block  immediately 
west  thereof,  three  brick  buildings  on  the  north  and  one  on 
the  south,  the  Montgomery  Block — all  Class  C  buildings, 
but  the  U.  S.  Customs  House  is  very  massive. 

(4)  The  U.  S.  Mint,  at  Fifth  and  Mission  streets,  saved 
by  its  lo-cal  well  and  pump  and  by  the  efforts  of  the  mint 
officials  and  employees  and  U.  S.  troops.    Class  C. 

(5)  The  U.   S.  Post  Office  at    Seventh    and    Mission 
streets.    Class  A.     (Badly  damaged  by  the  shock,  being  on 
a  thin  sand  layer  overlaying  a  marsh.) 

(6)  The  buildings  on  the  east  side  of  Guerrero  street, 
near  Ridley  street. 

BOUNDARY  OF  THE  BURNED  AREA 

The  burned  area  is  bounded  as  follows :  The  waterfront 
of  the  bay  from  Townsend  to  Taylor  street,  thence  obliquely 
and  along  intervening  streets  southwesterly  to  Van  Ness 
and  Filbert;  thence  along  Van  Ness  to  Clay  street,  along 
Clay  to  Franklin,  along  Franklin  to  Sutter,  and  thence  to 
Van  Ness;  along  Van  Ness  to  Golden  Gate,  along  Golden 
Gate  to  Fell,  along  Fell  and  Oak  to  Gough  and  Market,  out 
'Market  south  side  to  Ridley,  Ridley  to  Dolores,  Dolores  to 
Twentieth,  Twentieth  to  Valencia,  obliquely  across  blocks 
and  streets  to  Howard  and  Eighteenth,  along  Howard  to 
Fifteenth,  obliquely  across  blocks  and  intervening  streets  to 
Bryant  and  Eighth,  along  Eighth  to  Townsend,  and  thence 
to  the  Bay. 

A  fire  front  of  49,305  feet  or  9.34  miles. 
Waterfront  "     9,510    "     "  1.80    " 
Total 58,815   "     "11.14    " 


Confronting  this  line  on  the  unburned  side  were  527 
buildings,  of  which 

506  are  wood 
18    "  brick 
1    is  stone 
1   "  adobe 
1    "  corrugated  iron. 

The  fire  was  thus  stopped  against  a  wall  of  buildings, 
94  per  cent  of  which  are  wood. 

Of  this  49,305  feet  of  frontage,  9,540  feet  are  on  the 
wide  streets  or  avenues — Van  Ness  avenue,  Market  and 
Dolores  streets.  The  remainder,  39,765  feet,  are  on  ordinary 
streets,  across  blocks,  etc. ;  or  about  20%  of  the  total  front- 
age is  on  wide  streets,  and  the  remainder,  80%,  on  ordinary 
streets,  etc. 

FIRE  EFFECTS 

In  wooden  and  Class  "C"  buildings,  absolute  destruction 
by  fire  was  the  universal  rule  except  in  a  few  notable  in- 
stances mentioned,  where  service  reservoirs  and  pipes  on  firm 
ground  enabled  the  Fire  Department  to  work  effectively. 
Very  remarkable  and  effective  work  in  extinguishing  fires 
was  noted  in  the  following  instances: 

Wooden  buildings  on  the  northwest  corner  of  Golden 
Gate  avenue  and  Buchanan  street,  covering  a  50  vara  lot 
and  surrounded  on  all  sides  with  wooden  buildings,  caught 
fire,  and  were  'burned  on  the  morning  of  April  18th,  adjoin- 
ing buildings  put  out  and  saved.  The  two-story  building  on 
the  northwest  corner  of  Laguna  and  Hayes  streets  was  set  on 
fire  by  upsetting  drugs  and  chemicals,  and  nearly  entirely 
burned;  adjacent  wooden  buildings  were  saved.  A  large 
wooden  building  on  the  corner  of  Mission  and  22nd  streets 
was  entirely  burned,  but  immediately  adjacent  wooden 
buildings  were  saved.  These  instances  show  that  with  an 
adequate  water  supply,  the  effective  suppression  of  incipient 
fires  would  have  been  passible. 

Class  "B"  buildings  failed  in  the  fire  from  inadequately 
protected  girders  and  posts  and  a  lack  of  window  protec- 


tion.  Fire  shutters,  properly  constructed,  and  wire  glass 
would  have  saved  many  of  these  building's  and  their  eon- 
tents.  The  fire  gained  access  to  these  buildings  through  in- 
adequately protected  openings,  and  the  posts  and  girders 
collapsed  for  lack  of  protection.  The  fire  softened  inade- 
quately protected  iron  work;  as  this  collapsed,  the  walls, 
in  many  instances,  were  damaged  or  destroyed.  This  should 
be  prevented  by  heavier  and  better  covering,  even  at  the 
expense  of  room. 

Class  "A"  buildings  suffered  less  severely,  although 
most  of  the  fire  damage  to  these  buildings  was  also  due  to 
inadequate  protection  of  posts  and  girders  and  to  thin  parti- 
tions. An  instance  of  total  collapse  of  this  class  of  build- 
ing was  on  the  southeast  corner  of  Jones  and  Turk  streets. 
Here  the  steel  work  was  barely  inside  the  limit  of  strength 
required,  and  the  fire  protection  to  posts  and  girders  was 
flimsy;  consequently  the  entire  structure  collapsed  when 
the  contents  were  burned. 

Partial  collapse  of  columns,  in  individual  instances,  was 
also  found  to  have  taken  place. 

GENERAL  OBSERVATIONS  ON  THE   EFFECTS  OF  EARTH- 
QUAKE AND  FIRE  UPON    CLASSES    OF    BUILDINGS,  ETC. 

Under  headings  approved  by  the  committee,  its  investiga- 
tions covered  buildings  of  all  classes  used  throughout  the 
city,  and  each  type  has  been  examined.  For  prudential 
reasons,  it  is  considered  best  to  cite  typical  cases  rather  than 
specific  instances.  The  committee  will  deal  first  with  earth- 
quake effects  on  each  type  of  structure,  and  when  consider- 
ed necessary  will  cite  typical  examples. 

EFFECTS    OF    EARTHQUAKE    UPON 

(1)  Small  frame  buildings,  wooden  underpinning: — In 
general,  these  buildings  suffered  severely  owing  to  the  rotten 
condition  or  original  weakness  of  the  underpinning.  The 
mud  sills  and  adjacent  parts  of  posts  and  braces  had  in  many 
instances  rotted,  and  the  buildings  settled  vertically,  as  in 
a  row  of  frame  buildings  on  the  west  si3e  of  Webster  street, 

7 


between  Eddy  and  Turk  streets ;  or  they  settled  laterally,  as 
in  the  case  of  one-story  frame  'buildings  on  the  southeast 
corner  of  Bush  and  Steiner  streets,  and  on  the  south  side 
of  O'Farrell,  near  Devisadero  street.  In  most  instances  of 
this  kind  very  flimsy  construction  was  originally  permitted. 
The  damage  to  the  upper  parts  of  these  buildings  was  at 
times  so  severe  as  to  totally  wreck  the  buildings. 

Small  frame  buildings  with  masonry  foundations  stood 
well,  the  damages  being  generally  restricted  <to  loss  of  chim- 
neys and  consequent  injuries  to  roofs,  walls  and  gutters. 

(2)  Large  frame  buildings,  wooden  underpinning: — In 
general,  a  stronger  original  construction  and  broader  base 
enabled  these  structures  to  stand  well.     Damages  to  roofs 
and  sides  by  falling  of  chimney  tops  from  the  building  itself 
or  from  adjacent  buildings  constituted  the  major  portion  of 
the  damage.    In  some  instances,  the  roofs  were  not  able  to 
withstand  massive  chimneys  with  high  fall. 

When  masonry  foundations  were  provided,  these  build- 
ings suffered  less,  and  numerous  instances  were  observed 
where  no  damage  whatever  was  done,  notably  the  three- 
etory  frame  building  on  the  northeast  corner  of  Washington 
and  Gough  streets,  where  the  chimneys,  by  reason  of  first- 
class  construction,  remained  intact,  and  the  building  itself 
shows  no  evidence  of  strain.  It  may  be  here  observed  that 
buildings  of  this  type,  we'll  constructed,  diagonally  boarded 
and  braced,  metal  or  wire  lathed,  and  with  chimneys  of  re- 
enforced  concrete  or  brick,  well  laid  in  cement  mortar,  are 
perfectly  safe  in  a  severer  shock  than  that  of  April  18,  1906. 

(3)  Class  "C,"  brick  walls,  wooden  partitions,  floors 
and  posts: — This  class  -of  structure  has  quite  a  variety  of 
applications,  being  used  for  dwellings,  stores,  storehouses, 
churches,  libraries,  etc.     When  properly  constructed  they 
stood  the  shock  well,  particularly  if  the  walls  were  tied  and 
bonded  and  the  mortar  good.     'Some,   however,  had  two 
fatal  defects,  one,  weak  or  badly  laid  mortar,  the  other,  an 
inherent  defect — unsupported  gable  ends.    Churches,  large 
storehouses,  earhouaes,  barns,  etc.,  were  injured,  the  gable 
ends  being  especially  weak.     This  defect  has  been  brought 

8 


out  prominently  in  this,  as  well  as  in  higher  classes  of  'build- 
ings. Notable  instances  are  on  the  northeast  corner  of 
California  and  Webster  streets,  the  south  end  of  the  Ferry 
Building  (Class  "A").  Numerous  other  instances  were 
observed,  especially  where  lime  mortar  had  been  used,  not 
at  all  or  but  slightly  strengthened  by  the  addition  of  Port- 
land cement;  and  where  fairly  good  mortar  had  been  badly 
used  or  the  bricks  laid  dry,  instead  of  soaking  wet,  as  they 
should  be  in  good  work. 

A  marked  instance  of  failure  from  poor  mortar  is  on 
the  south  side  of  Geary  street,  near  Fillmore,  wh^re  well 
bonded  'brickwork  fell  to  pieces,  and  stone  veneer,  without 
bond,  scaled  off  the  lower  story.  This  scaling  is  frequently 
the  case  in  the  pressed  Roman  used  as  face  brick,  without 
b'ond,  or  fastened  against  wooden  buildings  with  weak  metal 
ties.  Failures  from  these  causes  have  been  so  general  that 
they  have  caused  universal  comment,  and  it  is  hoped  that  the 
lessons  will  result  in  the  thorough  testing  of  all  cements 
and  other  materials  and  their  proper  use,  as  a  matter  of 
safety,  not  only  to  the  owner  'but  to  the  public  in  general. 

Equally  notable  cases  of  the  standing  of  well-built 
structures  are  frequently  noticed.  The  U.  S.  Appraisers' 
Building  on  Sansome,  Washington  and  Jackson  streets, 
although  partly  on  made  ground,  did  not  suffer  the  slight- 
est injury,  due  to  the  excellent  quality  of  mortar  and  good 
workmanship.  A  seven-story  building  on  the  south  side  of 
Eddy  street,  one  hundred  feet  east  of  Jones,  although  sub- 
sequently burned,  its  walls  of  well-bonded  brick,  with  good 
mortar,  stand  intact.  Other  instances  are  the  Jewish  Taber- 
nacle on  the  north  side  of  Sutter  street,  between  Stockton 
and  Powell  streets,  the  church  on  the  northwest  corner  of 
Fillmore  and  Jackson  streets,  and  the  one  on  the  southeast 
corner  of  Fillmore  and  Fell  streets. 

(4)  Class  "B,"  brick  or  masonry  walls,  steel  or  cast 
iron  posts,  and  steel  girders  protected  against  fire,  metal 
lathed  partitions,  etc.: — The  damage  to  this  class  of  build- 
ings by  earthquake  was,  in  general,  light;  no  instances  of 
well-constructed  buildings  of  this  type  were  observed  which 

9 


suffered  more  than  a  small  percentage  of  damage.  A  not- 
able instance  is  the  re-enforced  and  well-built  walls  of  the 
Palace  Hotel,  which  withstood  both  fire  and  earthquake. 

(5)  Class  "A,"  steel  frame,  non-combustible  floors  and 
partitions: — The  thoroughness  with  which  these  structures 
withstood  the  earthquake  has  'been  so  frequently  recorded 
that  it  is  not  necessary  for  the  committee  to  farther  note 
the  facts.    The  most  severe  injury  was  to  the  slim  and  heavy 
tower  of  the  Ferry  Building,  and  the  south  unsupported 
gable  end.     This  structure  stands  entirely  on  piles,  eighty 
to  ninety  feet  long,  driven  into  harbor  mud  some  fifteen  to 
twenty  feet  below  city  base.     Yet  it  withstood  the  shock, 
wih  the  exceptions  above  mentioned  and  a  few  minor  inju- 
ries to  marble  wainscoting.    Another  instance  of  damage  to 
this  class  is  the  north  wall  of  the  building  on  Sacramento 
and  Mason  streets.     Buildings  of  this  class,  in  process  of 
construction,  were  injured  whsre  mortar  had  not  yet  set, 
but  hardly  a  joint  was  sprung  in  those  which  were  caught 
with  the  frames  partly  constructed. 

With  corrections  as  to  fire  coverings  of  posts  and  beams 
and  the  use  of  metal  frames  for  doors  and  windows,  with 
wire  glass  and  proper  window  protection,  it  'has  been  demon- 
strated that  this  class  of  buildings  will  withstand  both  fire 
and  earthquake,  and,  with  a  local  supply  of  water,  can  be 
made  absolutely  safe,  even  in  a  general  conflagration.  But 
no  building  in  which  combustible  material  is  stored  will 
escape  a  general  conflagration,  unless  an  adequate  water 
supply  and  men  to  use  it  are  available.  Inferior  buildings, 
under  these  conditions,  were  saved,  and  superb  class  "A" 
buildings,  without  water,  were  totally  destroyed.  This  lesson 
cannot  be  too  thoroughly  impressed  upon  owners  and 
officials. 

(6)  Effects  of  earthquake  on  high  stacks  and  chim- 
neys:— These  structures  were  generally  severely  damaged 
or  broken.     They   are   of  several   cross  sections,   circular, 
square,  polygonal,  and  intersecting  squares.    Those  having 
square  sections  appeared  to  stand  best.    The  percentage  of 
stacks   escaping  injury   is  so   small   that  your  committee 

10 


recommends  that  in  future  these  be  entirely  of  metal  or 
of  heavily  re-enforced  concrete  or  re-enforced  brick-work; 
in  these  two  latter  cases  that  only  cement  mortar  of  the 
highest  strength  be  used. 

Chimneys: — Chimneys  suffered  proportionately  more  sev- 
erely than  anything  else.  This  was  'due  to  three  causes: 
(1)  worthless  mortar;  (2)  bad  workmanship,  and  (3)  unusual 
strains  at  the  joints  of  roofs  with  the  chimneys  where  weak- 
ened further  by  flashings.  To  overcome  these  defects  will 
be  simple  'but  will  require  good  materials  and  first-class 
workmanship.  Chimneys  stood  where  well  constructed, 
proving  that  well  selected  materials  and  good  workmanship 
are  proof  against  severer  shocks  than  that  lately  experienc- 
ed. To  accomplish  this  result,  your  Committee  recommends : 
first,  that  either  lime  mortar  of  standard  proportions,  re- 
inforced with  one-third  PortlanI  cement,  or  Portland  cement 
mortar  be  used  with  reinforcing  steel  rods  at  roof  joint  and 
above ;  or,  second,  that  reinforced  concrete  of  the  best  qual- 
ity be  used. 

Flue  linings  have  resulted  in  placing  reliance  upon  thes3, 
and  using  flimsy  brickwork  on  the  outisde.  The  'brick  chim- 
neys properly  built  are  safe  and  strong  under  any  condi- 
tions yet  experienced,  and  the  linings  serve  as  a  subterfuge 
to  lessen  the  cost  and  efficiency  of  one  of  the  best  materials 
of  Which  chimneys  can  be  built,  namely,  good  brickwork. 

Mortar: — The  results  warrant  the  absolute  rejection  in 
the  future  of  lime  mortar  unless  well  seasoned  and  reinforc- 
ed with  Portland  cement,  and  the  most  stringent  supervision 
be  had  over  the  testing  and  use  of  this  latter.  Inferior 
cement  and  poor  workmanship  will  make  weak  structures 
ready  to  fail  when  the  test  of  actual  strain  or  use  comes. 
Every  yard  of  concrete  and  every  brick  laid  in  the  future 
should  be  mixed  and  laid  with  scrupulous  care.  Concrete 
can  be  made  as  worthless  as  much  of  the  brickwork  was  in 
this  city.  Hence  it  must  be  made  of  the  best  materials, 
properly  mixed,  laid  and  rammed  to  secure  good  results; 
and  bricks  must  be  sound  and  well  made,  carefully  laid 

11 


when  soaking  wet  in  the  best  lime-cement  or  cement  mortar. 
These  classes  of  work  will  insure  safety  in  earthquake  shocks 
of  greater  severity  than  that  exprienced  in  April,  1906, 
and  with  the  added  security  of  an  ample  water  supply, 
proper  protection  of  posts  and  girders,  and  guarded  openings 
to  all  masonry  buildings,  will  make  such  general  and  wide- 
spread disasters  as  that  following  the  morning  of  April  18th, 
1906,  absolutely  impossible. 

(7)  Retaining  walls: — Retaining  walls  have  long  been 
a  source  of  expense  and  danger  in  San  Francisco,  the  per- 
centage of  these  failing  from  various  causes  has  always  been 
large.    In  a  city  of  such  variations  of  level  they  are  neces 
sarily  much  used.    Both  ordinary  and  surcharged  walls  fail- 
ed from  lack  of  sufficient  gravity  section  and  inadequate 
footings.    An  instance  of  both  of  these  deficiencies  is  in  the 
overturned  surcharged  wall  on  the  west  side  of  Gough  street, 
between  Pacific  street  and  Broadway.     Instances  of  each 
were  noted.     As  examples    of    well-constructed    retaining 
walls,  the  committee  notes  those  on  Pine,  Powell  and  Mason 
streets,  and  on  the  south  side  of  California  street,  west  of 
Presidio  avenue,  which,  with  others,  withstood  the  shock 
without  injury,  proving  that  properly  constructed  retain- 
ing walls  can  be  relied  upon  with  confidence. 

(8)  Monuments  and  Statuary: — These  slender  structures 
withstood  the  shock  well.     In  cemeteries,  some  were  over- 
thrown.    The  Dewey  Monument  in  Union  Square  was  re- 
ported "standing  at  an  angle  of  ten  degrees."    An  inspec- 
tion shows  that  the  sections  were  barely  displaced  and  the 
pedestal  very  slightly  spalled  at  a  few  joints,  and  that,  to 
the  ordinary  eye,  the  monument  stands  unscathed  by  either 
earthquake  or  fire.    Monuments  and  groups  of  statuary  in 
other  portions  of  the  city  were  uninjured. 

In  conclusion,  the  Sub-Committee  on  Statistics  finds : 

(1)  That  well-built  structures  of  all  classes,  generally 
withstood  the  earthquake  without  serious  injury,  and  that 
the  majority  of  these  structures  were  unharmed. 

12 


(2)  That  the  principal  damage  by  earthquake  was  due 
to  inferior  workmanship,  worthless  mortar,  or  faulty  design. 
As  instances  the  City  Hall,  in  which  the  design  of  the  build- 
ing is  radically  unsuited  both  to  the  requirements  and  to 
the  strains  liable  to  occur.    Immense  gable  ends  and  cornice 
resting  upon  massive  columns,  not  well  tied  to  the  remainder 
of  the  'building,  were  the  cause  of  damage  to  a  far  greater 
extent  than  inferior  mortar  and  workmanship,  as  has  been 
alleged.     The   fragments  of  masonry  lie  in  large   masses 
rather  than  in  individual  bricks,  as  in  many  other  fallen 
walls.    The  same  is  true  of  the  church  on  Bush  and  Pierce 
streets,  and  other  instances.     These  are  defieiences  which 
can  be  remedied  in  the  future. 

(3)  That  losses  by  fire  were  in  the  greater  part  due: 
(a)  to  the  utter  failure  of  the  pipe  system,  as  made  mani- 
fest by  the  extinguishment  of  fires  where  a  meagre  water 
supply  was  available;  (b)  to  lack  of  protection  to  openings 
in  masonry  buildings,  and,  in  the  burned  buildings  of  classes 
"B"  and  "A,"  to  the  additional  lack  of  adequate  fire  cov- 
erings for  posts  and  girders,  causing  collapse  of  these  mem- 
bers in  class  "B"  and  in  some  instances  in  class  "A"  build- 
ings.   These  are  also  defects  which  can  be  remedied  so  as 
to  lessen  insurance  risks  and  rates  and  ultimate  damage  in 
case  the  contents  of  these  structures  should  burn. 

(4)  That  class  "C"  buildings  constitute  the  poorest 
and  most  dangerous  structures,  and  should  'be  restrictad  in 
use,  steel  framed  and  galvanized  iron  sides  and  roofs  being 
preferable.    Also  that  a  greater  use  should  be  made  of  non- 
combustible  materials,  steel,  concrete,  galvanized  iron,  metal 
lathing,  etc.,  than  the  present  fire  and  building  laws  admit. 
This  will  be  to  the  advantage  of  owners  and  the  greater 
safety  of  the  city. 

(5)  The  members  of  this  Sub-Committee  feel  that  too 
great  importance  cannot  be  laid  upon  the  thorough  inspec- 
tion and  testing  of  cement  and  other  building  materials  and 
upon  the  most  conscientious  workmanship,  and  are  assured 
that  craftsmen  of  all  branches  cannot  render  a  greater  ser- 
vice to  the  community  nor  to  themselves  than  by  refusing 

13 


to  do  work  of  any  kind  which  is  not  up  to  a  high  standard 
of  workmanship;  for  neither  themselves,  their  families,  nor 
any  one  else  will  be  safe,  nor  -property  secure,  with  such 
flimsy  work  as  has  characterized  many  buildings  of  all 
classes  of  structures  in  this  city. 

Streets  and  lots  graded  with  waste  and  loose  materials 
of  all  kinds  are  not  suitable  foundations  on  which  to  make 
sewers  amd  pavements  nor  erect  homes  or  buildings  for 
human  occupation  and  use,  nor  are  sewers  and  buildings 
with  inferior  mortar  and  poorly  laid  brick  on  filled  areas 
of  this  kind  more  likely  to  stand  in  the  future  than  in  the 
past. 

The  causes  of  our  great  losses  may  therefore  be  briefly 
stated : 

(1)  Failure  of  water  supply,  due  to  insufficient  number 
of  service  reservoirs  and  cisterns,  and  to  fractures  of  the 
mains  and  connections  where  constructed  over  made  ground 
and  marshes  and  over  or  immediately  adjacent  to  faults. 
Mains  should  be  altogether   on   solid    ground,    or   on    the 
heaviest  of  masonry  and  pile  foundations,  and  service  reser- 
voirs and  cisterns  should  be  more  numerous  and  larger. 

(2)  Flimsy  construction,   and,  in  some  instances,  im- 
proper design. 

(3)  Absence  of  adequate  door  and  widow  protection  for 
masonry  buildings. 

(4)  Lack  of  efficient  covering  for  posts  and  girders  in 
classes  "B"  and  "A." 

The  necessity  for  constructing  buildings  of  incombustible 
materials  has  been  made  fully  apparent.  These  buildings 
must  meet  all  requirements,  from  the  costly  and  elaborate 
steel  cage  concrete  walled  and  floored  structure  with  metal 
doors,  windows  and  finishings,  to  the  cheap  steel  framed 
shed,  covered  and  roofed  with  galvanized  iron.  To  meet 
these  requirements,  the  following  sub-classes  of  class  "A" 
are  suggested : 


14 


Class  "A"  1 

Steel  cage  construction  concrete  brick  or  tile  walls  and 

floors, 
Metal  framed  doors,  windows  and  finishings,  plate  wire 

glass  windows,  asbestos  curtains  inside. 

Class   "A"   2 

Concrete  or  brick  walls, 
Steel  posts  concrete  or  tile  covered, 
Concrete  steel  or  tile  floors, 
Steel  framed  metal  covered  roof, 
Fire  shutters. 

Class  "A"  3 

Re-enforced    concrete    walls,    steel    framed    roof    metal 
covered. 

Class  "A"  4 

Light  steel  frame, 

Walls  metal  lathing  or  expanded  metal,  plastered  with 

cement  mortar  on  one  or  both  sides  of  framework, 
Concrete,  steel  or  tile  floors, 
Metal  roof, 

Metal  framed  windows  and  doors, 
Plate  wire  glass, 
Asbestos  curtains,  for  light  stores  or  dwellings,  etc. 

Class  "A"  5 

Steel  frame,  corrugated  iron  sides  and  roof  for  sheds 
and  lightest  buildings. 

If  more  than  one  story,  upper  floors  of  steel  and  concrete 
or  tiles. 

Class  "A"   6 

Any  combination  of  the  above  classes  which  are  struc- 
turally sound. 

15 


It  will  be  observed  that  each  of  these  classes  is  composed 
of  incombustible  materials,  that  they  vary  in  cost  from  the 
costly  sky-scraper  to  a  cheap  steel  framed  galvanized  iron 
shed,  and  will  thus  meet  the  wide  requirements  of  cost,  and 
at  the  same  time  afford  a  reasonable  but  imperative  safety. 

Mortar  to  be  either  lime  cement  mortar  or  cement  mortar. 

If  the  radical  deficiencies  above  outlined  be  remedied, 
San  Francisco  will  have  but  little  to  dread  from  even  a  more 
serious  earthquake  than  that  of  April  18th,  1906 ;  and  if,  in 
rebuilding,  we  make  stability  and  thoroughness  the  prime 
essentials  of  all  work,  these  characteristics  will  mark  our 
recovery  and  development  in  every  line  to  the  remotest 
future. 

LOSS  OF  LIFE 

Loss  of  life,  lamentable  as  it  was,  was  by  reason  of  the 
earliness  of  the  hour  comparatively  slight.  That  such  im- 
mense property  loss  should  be  incurred  with  so  slight  a 
death-list,  is  a  noble  testimony  to  the  spirit  of  the  people  and 
to  the  directing  forces  brought  to  bear  upon  the  catastrophe. 
Killed  outright  and  accounted  for  at  the  Coroner's  office: 

Killed 315 

Shot  for  crime 6 

"     by  mistake  1 

322 

Reported  missing  and    not 
accounted  for. .  352 


Total 674 

There  are  many  who  have  stated  to  the  Sub-Committee 

that  the  loss  of  life  was  greater,  but  such  statements  are 

founded  on  belief  not  fact.   The  Sub-Committee,  therefore, 

do  not  feel  justified  in  going  beyond  the  figures  above  given. 

Respectfully  submitted, 

Edwin  Duryea,  Jr., 
Virgil  G.  Bogue, 
James  W.  Reid, 
Maj.  C.  H.  McKinstry, 
Wm.  Curlett. 

Marsden  Manson,  Chairman. 
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